1. Field of the Invention
The present invention relates to a socket for electrical parts, which detachably holds an electrical part such as an IC package on a mounting portion thereof and connects the electrical part electrically to an external circuit, and more particularly, relates to a socket for electrical parts, capable of improving the heat dissipation capability of a heat sink which dissipates the heat generated from the electrical part, when in contact with the electrical part mounted on the mounting portion, and also capable of preventing damage to the electrical part.
2. Description of the Related Art
Conventionally, in the testing of the performance of electrical parts such as a BGA type IC package for example, a socket is used for electrical parts, which detachably holds an electrical part on a mounting portion thereof and electrically connects the electrical part to an external measuring apparatus such as a circuit. A conventional socket for electrical parts of this type includes a socket body on which is formed a mounting portion for mounting an electrical part such as an IC package; a plurality of contact pins disposed on the socket body and capable of connecting with respective connection terminals provided on a lower surface of the IC package which is mounted on the mounting portion; and heat sinks attached to a pair of left and right opening/closing members that can be opened/closed by operation of operating members provided on the socket body, for dissipating the heat generated from heat generating locations of the IC package in a state where the opening/closing members are closed and the heat sinks are in contact with the IC package.
In addition, such a socket for electrical parts is designed so that when downward pressure is applied to the operating members, the heat sinks attached to the pair of left and right opening/closing members are opened out towards the left and right. Furthermore, when the downward pressure is released, the heat sinks having been opened to the left and right are closed, to cover the mounting portion of the socket body. Consequently, in order to hold the IC package in the socket, first the heat sinks are opened and the IC package is mounted on an upper surface of the mounting portion, and then the opened heat sinks are closed. At this point, the heat sinks are in contact, at a predetermined pressure, with the IC package mounted on the mounting portion, thereby securing the IC package.
Performance testing of the IC package held in the socket is carried out by electrically connecting the respective connection terminals of the IC package to an external testing apparatus via the plurality of contact pins. While the performance testing is being carried out, the heat generated from the heat generating locations of the IC package is conducted through contact surfaces of the heat sinks being in contact with the IC package, and then transmitted and dissipated into the open air (into the atmosphere) from cooling fins formed on the heat sinks.
However, in such a conventional socket for electrical parts, the heat sinks are formed entirely from a lightweight material such as aluminum, in order to minimize a load applied to the IC package when the heat sinks are closed and pressure is applied to the IC package. Consequently, sometimes the heat generated from the IC package during the performance testing of the IC package is not conducted sufficiently to the contact surfaces of the heat sinks, and the heat cannot be dissipated effectively from the cooling fins into the open air. Accordingly, there is a possibility that heat is accumulated inside the IC package and the socket for electrical parts, causing damage to the IC package.
Furthermore, in the conventional socket for electrical parts, there is a predetermined limit to the size of the contact surfaces of the heat sinks that dissipate the heat generated from the IC package into the open air. For example, as shown in FIG. 15, in the case where contact surfaces 51 of left and right heat sinks 50 are formed so as to project further outward than outside edges of an IC package 40 when the left and right heat sinks 50 are closed, there is a possibility that edge portions (see (a) in FIG. 15) of the IC package 40 are damaged by the contact surfaces 51 of the heat sinks 50. Or, sometimes inside bottom edges (see (b) in FIG. 15) of the contact surfaces 51 of the left and right heat sinks 50 are in contact with each other, causing the heat sinks 50 to be broken or deformed. Therefore, as shown in FIG. 16, it is necessary for the heat sinks 50 to be formed such that the contact surfaces 51 thereof do not project further than the outside edges of the IC package 40. In such a case, sometimes the entire area of the contact surfaces 51 of the left and right heat sinks 50 is less than the surface area of the IC package 40, resulting in that the heat generated from the IC package 40 cannot be conducted sufficiently to the contact surfaces 51 of the heat sinks 50, and therefore cannot be dissipated into the open air. Consequently, there is a possibility that heat accumulates inside the IC package and the socket for electrical parts, causing damage to the IC package.